1. Field of the Invention
This invention relates to a method for producing trehalose, which is useful as a stabilizer of pharmaceuticals and also widely useful in the field of food processing.
2. Description of the Prior Art
Trehalose is one of disaccharides widely distributed in natural products such as yeasts, mold, marine animals, seaweeds, etc. As the methods of obtaining this substance, there have been known, among others, methods comprising extraction from the above-mentioned natural products or fermentation by microorganisms which are capable of producing trehalose, e.g. those belonging to the genus Arthrobacter [Agricultural and Biological Chemistry 33 190, (1969)] or those belonging to the genus Nocardia (JPA 50-154485). These methods are hardly workable for mass-production or require a great deal of energy accompanied with complicated operations and equipment of a large scale so as to refine the products to such an extent as to make them safely usable as pharmaceuticals or foodstuff. The yield of trehalose in the method is unsatisfactorily low. There has been known another method which comprises converting maltose into trehalose by the aid of an enzyme such as maltosephosphorylase, trehalosephosphorylase or the like (JPA 58-216695). In this method, however, a relatively high cost is required for preparation of the enzymes, and no method of producing trehalose at low cost and also in a large amount has yet been established.